Distinguished Member

An ND2 will reduce the lumen output by approx 50%, though it won't look as reduced as that. An ND4 etc will reduce it further.

I find the Hoya HMC range to be the best opticaly, but they can be quite expensive if you want the larger sizes, so you could try Ebay. Otherwise Jessops sell them, though other places do them as well, you could try a google search amd see what turns up.

What thread size does the pj have (if it has one, otherwise measure the lens and see if you can fit one using tape or something like a rubber band).

Guest

The lens is not threaded and there is the motorised door to consider also, not much clearence. So should I try a ND2 filter or a CC30R, heard this mentioned on other threads. Have a basic idea what the difference is but wondered if anyone had any more insight.

Well-known Member

The cc30r is a red filter and you need some calibration software to get the colours right after fitting it so I would not recommend it.
Most people on here use the cc30r with the Z3 and Rones setings which are calibrated to D65. As far as I am aware Rone does'nt believe the cc30r filter is needed for the Z4.

Guest

I know that rone doesn't think a filter is neccesary but i personally would like to achieve better black levels as this is my preference and obviously a weeker area for LCD PJ's. So which filter should I try to achieve this?

Distinguished Member

Paul - just read what your screen size is and wondered what setting you're using? I saw Darko's Z4 today and it has a plethora of adjustments which can make deciding on which filter a problem. The black level can be very impressive with the iris fully shut and an ND4 attached, but the blacks still need help with some mid average picture level scenes.

If you use a setting that will allow full light output (vivid), then you will need at least an ND4 (maybe more - two filters may be a good idea and you can remove one later as the lamp dims with age if you think the overal brightness has reduced). If you use one of the theater modes then an ND2 will be fine. Living seemed like a good alternative. I think 'mid' looked like a good colour temp choice otherwise the colours were a bit too saturated (IMHO).

Very nice and smooth image with plenty of detail though, and no VB that I saw (using vga - we didn't have the right lead combination from htpc).

Guest

I use Rone's Creative Cinema derived setting's with the manual Iris stopped down to -63 and the lamp in eco mode. My main DVD source is a samsung HD850 over HDMI.

Obviously I don't mind changing my settings to whatever they need to be to get a decent black level but as a guide to my image preference I can live without the extra brightness in exchange for black.

It would just be nice to get rid of the grey bars when watching 2.35:1 material. Apart from the blacks and bad SD de-interlacing I think the Z4 is an awesome machine. When I complain about the blacks of the Z4 it is not just aimed at the Z4 but at LCD projectors in general. At my place of work we use pretty decent DLP's and 9" CRT projectors so I am predisposed to a good black and would just like this at home too!

Guest

I managed to find a Cokin ND4 filter to try out and was quite pleased with the results.

I found that using vivid as a starting point and calibrating the B&C and putting the lamp in low mode produced a very pleasing picture.

Only problem is that after a few hours of viewing the filter seems to have deteriated and now makes the image blurry! Is this normal for a filter to fail so quickly? The filter is a P153. I just rested it in the motorised door slot infront of the lens.

I think the filter is made from a resin, would a glass filter last more than a few hours?!

Think I may try a ND8 next time aswell just to bring the blacks down a fraction more but I was very happy with the ND4.

Distinguished Member

Some resin filters and thin plastic types can crinkle and melt from the heat of the light through the lens, but glass ones should be fine. I've used mostly Hoya filters (HMC range are best) with no detrimental effects after hundreds of hours.

Guest

The filter I have used is about 1.5mm thick plastic and doesnt look to have deformed but upon close inspection angling the filter away from the Pj lens you can see what looks like the surface/coating has been deformed slightly.

I like this filter because it is 82mm square so I can just rest it infornt of the lens without having to mount it. Do the glass Hoya filters only come with threads as i'm not sure i'm going to be able to mount it over my lens as I am using some vertical lens shift meaning there is no clearence under the lens. Not sure what the soloution is and the best way to mount a filter?

Do you know of a good online retailer that sell's the hoya filters? Would a simple gel be easier to use or will this just wrinkle after time from the heat?

Not sure if there is an easy way to mount it, but you may be able to make something up. I'm not that familiar with the PJ so hopefully other Z4 owners can help. Maybe if you post some pics of the filter next to the pj lens people might have a few ideas that might work.

Maybe 2 pieces of 6mm MDF in an L shape will work - lay the longer piece on top of the pj with the shorter piece in fron and holding the lens in place (make a hole just big enoigh for the filter to screw/fit into). Doing that measn you won't have to buy such a large filter; it just has to be big enough for the image to pass through,

Active Member

Gary, seems you know your stuff with filters - can you tell me if there is a neutral filter that'll only allow 1/6th available light through ?

i want to see what sort of effect this has on my picture - just as an experiment, and only for about twenty seconds and then i'll be done, so maybe just plastic filter ? but can you recommend something ? - i just need to take a photo of the screen with this much dimming to estimate how bright my screen will be with a particular light output from a lamp other than the uhp

Distinguished Member

An ND2 is the equivalent of a photographic 0.3, an ND4 is 0.6 and ND8 is 0.9 IIRC. They will reduce the image by half each time, but if you can find a 0.1 or 0.2 Kodak Wratten filter (gel. 0.1 is a third of an ND2 I think), you could add that to the ND4 to tget clsoe to what you're after. Lee Filters do a lot of gel type sheets of filter material for lighting and they may have what you want.

Guest

Thanks for the input so far Gary. Throwit, your a little bit scary, I was skimming your thread earlier actually by chance, adding a filter and playing around with a few settings is nothing compared to the kind of tweaking you are into!

Guest

Will do Gary, how hard can it be to find a couple of filters though, blimey! If anyone else knows of good suppliers then please post, will let you know how I get on with SRB.

Just to confirm, in the absence of any colour calibration instruments/software do you think that ND filters are the way forward if the main thing I want to do is improve black levels? From my initial tests with the ND4 (before it went all blurry!) I think I can get close to the picture I am after by going down this road.

Active Member

shame they don't have more stages of lamp brightness, like four output levels rather than just the two, or i bet that they could quite easily leave the factory with a fully variable lamp output, perhaps the z5, or z6, or z7...

Distinguished Member

If you just want to dim the image down and with minimal impact on the colours, the ND range are the best bet. If you need to remove an obvious green push, then a CCR or fl-day filter are good choices but some rebalancing of the colours will probably be needed. The SpyderTV can be used as a means to getting to D65 if you're really keen though. There is a thread or two which cover it here if you want to do a search and find out more.